It is well known to use permanent magnet structures in order to retain various ferrous objects such as paper clips and pins. More particularly, it is also known in the art to enclose a magnetic structure within a housing to allow a user to create various designs from individual magnetic particles on the housing.
For example, Jerry P. Kayle, U.S. Pat. No. 3,714,612, issued Jan. 30, 1973, discloses a magnetic toy by which a user may erect various bridging designs from small magnetic particles on a platform of the toy. The small magnetic particles are held together by magnetic forces created by a single two-pole permanent magnet within the toy. The toy further includes two magnetic pole pieces which are each juxtapositioned against one side of the permanent magnet. The two magnetic pieces extend up along the sides of the permanent magnet and then bend at a right angle and extend outward to form two semi-circular platforms for the toy. A strip of non-magnetic material between the two semi-circular platforms creates an air gap in the magnetic circuit. Therefore, the magnetic particles tend to form a bridging design between the two magnetic pieces. It is further noted that the extension of the magnetic pole pieces along the side of the permanent magnet between the north and south poles of the permanent magnet shunts the magnetic field and weakens the magnetic field for the toy of the Kayle patent.
Another magnetic toy is disclosed in Sam Gross, U.S. Pat. No. 3,906,658, granted Sep. 23, 1975. The Gross patent also teaches a magnetic toy which may be used to create bridgelike designs from magnetic particles on a platform of the toy. Gross, however, uses two bi-polar permanent magnet structures and a magnetic bar to form a U-shaped magnetic circuit. The two magnetic structures are arranged so that each structure has an opposite pole adjacent the platform of the toy. The magnetic particles thus seek to follow the magnetic field, which allows a bridgelike design to be held in place by magnetic forces.
The above-cited prior art references, however, do not disclose a magnetic toy in which an increased percentage of the surface area of the toy platform is in contact with the magnetic structures so as to create a strong magnetic field on the toy platform. Furthermore, the above-cited references do not disclose a magnetic toy which produces a high strength magnetic field which can support both bridging and non-bridging, divergent designs.